When you upgrade there are million things that can mess up with it, that's why clean installing is the best thing to do, like it or not, reinstalling software doesn't take years, it's your laziness what happens. I had to install many big programs like 3dsmax and plugins and scripts, it only took me some minutes. so if you want it to work fine, don't be lazy and clean install. Because my windows 10 works really amazingly perfect, no problems with drivers, sound or video. no problems with apps or anything that didn't happen before. store works good, and Xbox opens nice and I updated my avatar and all. I have installed apps with no problem, no errors.
So if you want to have a good experience, and that means, your windows 10 is messed up already anyway. you could clean install it.
and rollback to go back to windows 10? that doesn't even make sense, I am sorry but you were asking so much for the Windows to roll you back just to go back to Windows 10, I am sure it was too much for the upgrade process and all the stuff it had to change back the first time going back to Windows 7/8.
It would have been easier just to reset your computer and tell it to keep your files and programs. but yeah, install windows 10 from mediacreationtool and a usb, and let Windows keep everything on Windows.old would be easier than having frustrated experience with windows 10.
I upgraded a laptop from 8 to 7 and it works nice too. so it's not the upgrade the problem, but the things you had installed, the things you did in your windows when you used it and going to 10, rolling back and stuff like that. But Windows 10 feels really good, it's pretty interface, even making 3dsmax look more modern without Autodesk doing anything so there is nothing I can't advice you but reinstall Windows 10 from zero (keeping your file of course)
Windows 10 has no many problems as you think, like I said, it works like the best thing ever. the only thing sucking is Windows Central crashing Edge, but commenting on forums are fine so I hope WC team fix it someday.